The answer is correct I just need the steps please.

It costs $34,000 to retrofit the gasoline pumps at a certain filling station so the pumps can dispense E85 fuel (85% ethanol and 15% gasoline). If the station makes a profit of S0.09 per gallon from selling E85 and sells an average of 20.000 gallons of E85 per month, how many months will it take for the owner to recoup her $34,000 investment in the retrofitted pumps? The interest rate is 0.75% per month. Click the icon to view the interest and annuity table for discrete compounding when i = 0.75% per month. It will take 21 months to recoup the investment. (Round up to the nearest whole number.)